Semi race motor advice

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whitehause
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Re: Semi race motor advice

Post by whitehause » Tue Jan 29, 2019 9:45 am

I appreciate all the advice from everyone......it's very valuable to hear from people who have "been there done that" !

Perhaps I should use the term "Hot street motor" from now on.... :D

I know there are a number of things that can, and most likely will, be done different in the future but the budget is what the budget is right now.
Since I have a admittedly light budget of $3000.00, some things have to be sacrificed. Just a duel carb set up and a manual trans conversion will be over $2000.00, and those are things that can be easily upgraded in the future. I my see if I can pick up a good used 40dcnf as Jim suggested though.
Right now I'm focusing on the motor internals since they will be the hardest to swap out in the future. I can do all the work myself, which will save a ton of money, and I have a great machine shop 1/2 mile from my house. Small family owned shop that has been passed down through generations. Old fashioned work ethic and old fashioned prices! Clean, magnaflux, bore, finish hone, match the pistons to the bores for 140.00. He's one of those guys that will say " I wasn't super happy with the deck, so I threw it on the machine and took .001 off just to be sure" but will still charge the original price.
I'm putting in new valves, springs, guides, cams, adjustable cam gears, and "massaging" the heads as I've done with my Harley's and Corvettes in the past using GC's book as a guide. New pistons, pins, rings. The rods are all in good shape, and within specs for out of round. They weigh within 3 grams of each other (which was surprising) Three weigh 815 with the #4 being 812gm. I'll take a hair off the three heavy ones to get them in the 812/813 range. I'll weigh the caps first, hopefully that's where the discrepancies lie and I can remove from there. If not then we go to the small ends and work down the rod to find the excess weight, but past that I'll leave them alone. Crank looks great as did the bearings when removed.(a big relief )
New oil pump and pan (baffled of course) New starter.

I'm putting a bunch of the budget into the suspension. New cross member (reinforced and seam welded) all new control arms and connecting linkage, new brakes and lines, wheel bearings, springs and shocks, new trailing arms for the rear (upper and lower). New floor pans, and the dreaded cross member frame reinforcement since I have to cut the old bolts out anyway.
Paint, bodywork which I'll also do myself since I have a ton of House of Color paint left over from various projects. not to mention fabing the roll cage.

With all that I'm right around 2800.00.
I'm fortunate to have a garage full of equipment already having restored a number of cars in the past. To attempt this starting from scratch would cost a small fortune in equipment alone. As with all projects like this, there will be surprises that come up (the broken cross member in this case) but welders, hammers, and a lot of elbow grease can overcome a number of otherwise expensive issues.

Again.....thank you all for your input, and keep it coming! Knowledge is the best tool of all!!
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SimcaBertone66
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Re: Semi race motor advice

Post by SimcaBertone66 » Tue Jan 29, 2019 10:53 am

Dude, love your plan, a "hot street" motor can be FN fast ride... love to see you get the TH 180 trans to work well for what you have in mind … post photos as you go … :D
Joe DeGasperis
whitehause
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Re: Semi race motor advice

Post by whitehause » Tue Jan 29, 2019 11:08 am

Thanks Joe,
I do have a thread with pics started in the Tech & advice section. It's the "follow along as I build a 79 spider" thread. I've been updating with photo's there. Have off today, so I'll be tearing down the rear end. I'm waiting for the machine shop to call about the block. He's inspecting it and will let me know what the bores will clean up at so I can order the pistons. He wants them in hand so he can match each bore to each piston. Then the fun really begins! ( well not for my wallet ) :shock:
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SimcaBertone66
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Re: Semi race motor advice

Post by SimcaBertone66 » Tue Jan 29, 2019 8:37 pm

1526782_626272607432166_605530944_n.jpg
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No regrets going to a single carburetor after two decades of twin IDF's .. 500 cfm Rochester .. a Jet Carburetor's 500 cfm Rochester, tweaked stock manifold and stock throttle cable
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Joe DeGasperis
whitehause
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Re: Semi race motor advice

Post by whitehause » Tue Jan 29, 2019 8:48 pm

Nice! When you say "tweaked" manifold, what did you need to do?
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SimcaBertone66
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Re: Semi race motor advice

Post by SimcaBertone66 » Tue Jan 29, 2019 10:55 pm

Gasket matched to intake port and enlarged runners and a fabricated adaptor to match the Rochester base … was able to mock up the same setup with an off the shelf Trans Adapt part from Summit ...
Joe DeGasperis
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friedman
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Re: Semi race motor advice

Post by friedman » Wed Jan 30, 2019 9:06 am

JD is slowly doing a V-8 conversion and he is starting with the carb.
Carl in Virginia
75 spider
83 Bertone
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SimcaBertone66
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Re: Semi race motor advice

Post by SimcaBertone66 » Wed Jan 30, 2019 9:58 am

As some of you may already know, the Jet Carburetor Rochester 2G is marketed as a "spec" carb for spec V8 powered class of circle track race cars. …. Besides, some here know Daniels Wilsons name in this crowd....he is reskinning a C3 Vette with slice and diced 124 Spider panels … got some photos here ….somewhere....
Joe DeGasperis
whitehause
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Re: Semi race motor advice

Post by whitehause » Wed Jan 30, 2019 1:18 pm

I have two 68 Vetts. Don't think I'd ever re skin one with fiat parts, though one of them is an old crazy 70's custom I restored a few years ago. It's my drag/go fast car. 468, 4Sp, 411 rear, full roller, nitrous injected, adrenalin rush.
Along with a few Bikes I have done.
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vandor
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Re: Semi race motor advice

Post by vandor » Thu Jan 31, 2019 9:44 am

My 2 cents:
42/82 cams are not that hot, your grandma could drive a car to the store with them, so should be no problem using those.
The 8mm dome pistons give ~11:1 compression ratio, so plan on getting fuel for such an engine.
Airplane fuel is not the best for racecars, as aircraft engines turn around 3000 rpm so the fuel is slow burning. May not be the best suited for a 7000 rpm car engine. Not that you can't use it, but if you can find race fuel then go with that.

I agree with others that a larger carb would make a big difference.

Another way to find cheap power (well, torque) is to go with a lower rear end from a standard trans Spider, either 3.9:1 or 4.3:1.
Csaba
Parts: http://www.autoricambi.us
Cars: http://italiancarclub.com/csaba/Fiat.html
'71 124 Spider, much modified
'72 124 Coupe, new project, ex-Pete, ex-Eli, ex-Jack car (all Mira members)
'73 124 Wagon, no floors
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